In a city as old as New York, it is expected that there were people who lived—and died—here in the past. When a disease like Yellow Fever or Typhoid hit the City, unclaimed bodies and bodies of the poor were placed into mass burial sites on open lands called a potter's field. As the centuries passed, many of these open fields in were converted into Manhattan's public spaces and parks, including Washington Square Park, Union Square Park, Madison Square Park, and Bryant Park. Most of the bodies were never moved during park construction, only covered up, and thus there are still thousands of dead bodies below each of these places today.

Learn more about Manhattan's old potter fields in this short video from our friends at Time Out and hosts Greg Young and Tom Meyers from the excellent Bowery Boys podcast.

If you think New York City's parks are crowded now, you should see how many people are buried below you. Lets rewind to the 1700s, when New York City was rampant with Yellow Fever, and more than 20,000 bodies were buried under Washington Square park, most of which are still there.